1. Field
The present application relates to emissive ceramic materials having low amounts of specific trace elements.
2. Description of the Related Art
Solid state light emitting devices such as light emitting diode (LED), organic light emitting diode (OLED) or sometimes called organic electroluminescent device (OEL), and inorganic electroluminescent device (IEL) have been widely utilized for various applications such as flat panel display, indicator for various instrument, signboard, and ornamental illumination, etc. As the emission efficiency of these light emitting devices continues to improve, applications that require much higher luminance intensity, such as automobile headlights and general lighting, may soon become feasible. For these applications, white-LED is one of the promising candidates and have attracted much attention.
Internal quantum efficiency (IQE) is the ratio of photons created by an emissive material to the photons absorbed by the same material. An increased IQE value can improve a lighting apparatus's energy efficiency; however, it can be difficult to reliably obtain phosphors with a high IQE.